1. Field of the Invention
The present invention relates to a workpiece positioning device used in positioning a workpiece at two different reference surfaces.
2. Description of Related Art
In some cases, at the time of machining a workpiece by a machine tool, the workpiece is pressed against two different reference surfaces to be positioned. Japanese Laid-open Patent Publication No. 5-050351 discloses that after a workpiece is placed on a Z-axis reference surface, the workpiece is pressed against an X-axis reference surface by using an X-axis cylinder, and then pressed against a Y-axis reference surface by using a Y-axis cylinder to three-dimensionally position the workpiece.
However, when a workpiece has a special shape, there is a possibility that pressing the workpiece against a reference surface causes rotational movement of the workpiece, and as a result, the workpiece may not be pressed perpendicularly against the reference surface. In such a case, the workpiece is held with a clearance formed between the workpiece and the reference surface, and the workpiece may not be precisely set in a machining jig.
The present invention has been made in view of such circumstances, and has an object to provide a workpiece positioning device capable of positioning a specially-shaped workpiece simultaneously at two different reference surfaces.